Sliding windows and other windowpanes, door panels, etc. that can move encounter an undesired high resistance to sliding at the rubber profiled strip seals against which these panes rest due to the naturally present surface character of the seals. It has therefore long been the practice to provide the profiled strands, at least in those peripheral regions where friction is encountered, with a surface overlay that favors sliding. This overlay, in the form of a preformed thin strip, is joined with the profiled strip while the latter is still in an unvulcanized state. During the course of the subsequent vulcanization, the overlay is bonded to the profiled strip. It was hereby possible to intimately and permanently bond to the rubber of the profiled strip even those overlay strips of otherwise difficult to process fluorocarbons, such as the tetrafluoroethylene known under the trademark Teflon. However, under extreme conditions, especially when the profiled strips were sujected to very high or very low temperatures, such as in tropical and artic regions, separation of the overlay strip from the profiled main strip occasionally occurred.
Since these fluorine-containing synthetic materials have such good sliding characteristics, it is desirable to be able to retain such characteristics in the overlay strips. An object of the present invention is to improve the adhesion or bonding that can be achieved between the overlay strip and the profiled strip.